When using the surface acoustic wave (SAW) sensor to measure strain directly, which is vulnerable to ambient temperature interference, the sensor will inevitably produce force temperature coupling effect. Therefore, this paper presents a new type of wireless passive SAW strain sensor design method that is adopting an external load and differential structure. The SAW device in the sensor is used as a transponder for the wireless sensor system, which is adopting the dualchannel reflective delay line differential structure. One of the channels, collecting an external capacitive strain gauges used as the external load sensor, senses the strain. And the other one, also collecting an external capacitive strain gauges used as an external reference load, is used to counteract the effects of temperature changes in the test environment. Based on the couplingofmodes (COM) theory, this paper has simulated the load sensor capacitance changes caused by the sensor response characteristics. Finally, the feasibility and effectiveness of this differential load SAW strain sensor are verified by experiment.